"You probably wouldn't know, but I'm the most insecure and overweight I've ever been," the "Keeping Up With the Kardashians" sibling confessed. "I'm over 200 pounds, so I want to drop weight and this will be a good start."

But Rob has a long road ahead of him in the dance department. "I'm not a confident dancer at all," he said. "And down the road ... I don't want to be that guy who doesn't dance at his own wedding!"

Rob's most famous sibling, Kim, already had her "DWTS" moment. "She just said, like 'You're going to be really nervous.' [But] I don't want her advice -- I don't need advice from someone who lasted, I think three weeks."

Kardashian had another motivator for doing the show: His mom-ager, Kris Jenner. "My mom pretty much forced me to do this show. She did it to Kim and now she's doing it to me! [She] just says, 'Smile and be yourself''"